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Hi, i am the owner of a 2014 Mercedes E400 biturbo, with 2996 cc engine, 250.000 km on board. From few weeks i got some errors about misfires on cylinder 2 or 3, one by one. Only P0300 and P0302 or P0303 errors. We changed the spark plugs, the coils on 2 and 3 cyl, the injectors on 2 and 3 cyl, hpfp and camshaft sensors. The misfires are less than before but still there. Idle is ok, if you drive the car with slow accelerations it's ok, only on hard accelerations the misfires occure. Do you know how to figure out the problem?
LEAN MISFIRES:
Look at your "Low Pressure pump" output pressure: stable or up/down surges?
1-- Mechanical issues :
Does pressure drop during hard acceleration?
How old is that in-tank filter ?
Now is the time to replace it, including large ring seal.
2-- Electrical concerns:
How low voltage deep during hard accelerations??
Display voltage on cluster during drive... yoyo?
3-phase LPFP controller replace defective caps?
Last edited by CaliBenzDriver; 10-14-2022 at 10:41 PM.
Wow...250K KM, awesome.
Mine of same year only 36K KM. Will need approx 43 years to hit 250K KM.
You best provide ownership and maintenance history as much as you can.
The car age is at an expensive age.
What kind of scanner and other specialty tool like oscilloscope kit and DIY skill do you have ?
There will be 2 kind of task for your car.
01. Replace aging/worn/expired components because they have reached/passed maximum service, but have not failed...but soon will fail.
02. Replace failed components which is contributing to current issue, which may be covered at task 1 and maybe not.
The car deserve task 1 taken care of first, regardless of you have issue or not or else it will contribute to more problems down the road.
Just keep this in mind, mechanical and electrical components DO age and get worn out. Your 250K KM is a lot of distance covered, by mileage the car is already a champion.
If you want to DIY this car for current problem and keep the car for say 3+ more years and 75K KM more, minimum proper tools will need to be available unless you want to start parts cannon.
Or use a good MB capable Indie ( non MB) workshop.
I can point you where to start looking aside from Cali's good advice, but you will need proper tools and the DIY skill.
Check cam position sensor and cam magnet connectors for signs of oil.
Pull plugs and inspect. Replace plugs if they haven't been done recently.
Consider replacing the coils. I did this (not specified by MB) and it makes a noticeable difference in smoothness. Coils degrade over time, the stress on the boot from the spark plug change process can weaken the connection to the spark plug.
Wow...250K KM, awesome.
Mine of same year only 36K KM. Will need approx 43 years to hit 250K KM.
You best provide ownership and maintenance history as much as you can.
The car age is at an expensive age.
What kind of scanner and other specialty tool like oscilloscope kit and DIY skill do you have ?
There will be 2 kind of task for your car.
01. Replace aging/worn/expired components because they have reached/passed maximum service, but have not failed...but soon will fail.
02. Replace failed components which is contributing to current issue, which may be covered at task 1 and maybe not.
The car deserve task 1 taken care of first, regardless of you have issue or not or else it will contribute to more problems down the road.
Just keep this in mind, mechanical and electrical components DO age and get worn out. Your 250K KM is a lot of distance covered, by mileage the car is already a champion.
If you want to DIY this car for current problem and keep the car for say 3+ more years and 75K KM more, minimum proper tools will need to be available unless you want to start parts cannon.
Or use a good MB capable Indie ( non MB) workshop.
I can point you where to start looking aside from Cali's good advice, but you will need proper tools and the DIY skill.
Thanks for your reply. I have an Aurel 808 scanner and other diy tools. Not an osciloscope but can get one if needed.
Check cam position sensor and cam magnet connectors for signs of oil.
Pull plugs and inspect. Replace plugs if they haven't been done recently.
Consider replacing the coils. I did this (not specified by MB) and it makes a noticeable difference in smoothness. Coils degrade over time, the stress on the boot from the spark plug change process can weaken the connection to the spark plug.
Check compression.
Report back.
Position sensor was oily and changed them. The magnets looks good. I have one new coil and swapped between cylinders but it doesn't change the error. Will check the compression on cylinders.
Check the ECU connector(s) for signs of oil. Oil from the sensors and magnets, if any, can migrate through the harness and reach the ECU. Spray with contact cleaner to remove oil from the contacts. Any oil in the harness will take time to migrate out, requiring repeated connector cleaning.
Your Information :
From few weeks i got some errors about misfires on cylinder 2 or 3, one by one. Only P0300 and P0302 or P0303 errors. We changed the spark plugs, the coils on 2 and 3 cyl, the injectors on 2 and 3 cyl, hpfp and camshaft sensors. The misfires are less than before but still there. Idle is ok, if you drive the car with slow accelerations it's ok, only on hard accelerations the misfires occure.
In theory, you are having a compression issue and low chance of an ignition issue, based on : I am assuming all parts replaced are genuine.
There is a compression test in Xentry, I hope Autel has the same under its MB menu.
The test is like an amperage relative compression but a bit different, where the Crankshaft angular speed of each cylinder is read on a 10 second dry crank. Dry = no fuel and ignition.
Where there is less compression, there is less resistance, the angular speed will be different.
This test , need engine to be up to operating temperature first.
On top is Xentry compression test, below it is typical oscilloscope cranking amperage test, which people call Relative Compression test.
Relative Compression test uses electrical load reading to relate to compression pressure.
Better compression cylinder let say needed 500 amps and lower compression cylinder will need less , say 400 or less depending on how leaky it is.
If your current clamp is 600 amps one, no worry use it, no need the 2,000 amps one.
Our engine if using traditional INRUSH current capable amperage clamp which is only like 20hz sampling, it will read approx 570 amps as peak.
The Pico because it is so fast, can read higher than 600amps peak.
Best place to read amperage for starter motor is at the PYRO fuse at battery positive, that big cable output of pyro fuse is dedicated to starter motor only.
Don't use main ground wire at suspension top mount, because that wire also carry other electrical load for the entire car, usually 20 amps with ignition ON and engine OFF.
The firing order for M276 3.5 NA or 3.0 Turbo is 1-4-2-5-3-6
If you do not have COP waveform sensor to use as cylinder 1 marker, you can always probe the voltage of the trigger for the COP.
Attached the wiring diag of the ECM. 3 + 2 documents in PDF.
========================
Mechanical pressure gauge for compression only test for peak pressure, it can identify condition but only kind of obviously bad condition/s,
which most likely a Xentry's crankshaft angular speed compression test or amperage based relative compression test will also show.
Below's value is only possible to read using mechanical pressure gauge.
=============================
Without a Xentry, you need to remove fuses or connectors for coils and fuel injector to do a no-engine-start or Dry Cranking test.
Too bad our engine and MB lines of engine probably, does not have CLEAR FLOOD MODE like most US cars to do Dry-Cranking. On a fuel-injected engine, if you depress the gas pedal, usually past 80%, the fuel system goes into what's called clear-flood mode. During this time, the computer shuts off the fuel injectors so no more fuel is delivered while you crank the engine; hence, you can clear the flood.
=================
There is Misfire Counter on Autel. On the Xentry is called Smooth Running, something like that.
This is a good one to read.
For now I am pointing you test method which does not need you to remove much components from the engine.
If your misfire is only at high engine speed : only on hard accelerations the misfires occure.
It could also be enough carbon build up on your intake valves to badly effect the airflow swirl.
See my 35,000KM engine carbon build up here : https://mbworld.org/forums/e-class-w...eaning-p2.html
and https://mbworld.org/forums/e-class-w...bad-liner.html
To at least see the carbon partially without removing the intake manifold, you need a twin camera boroscope like the one I use ( I useTeslong NTS500 ) for its 90 degree side view,
and still.... you need the aftercooler to be removed to spin crankshaft pulley.
If someone in your area has the PicoScope and the WPS-500X pressure transducer or its good enough equivalent
Do a cranking waveform analysis and and engine running Snap Throttle waveform analysis. It may pick up minor valve issues even for exhaust valves and leaking head gasket or vacuum leak or scored cylinder liner.
Should you do intake valve cleaning ? Yes, because I am sure your intake valves at 250K KM has enough carbon worthy to be removed. This is good for long term use of this car.
Vacuum leak........... can it be ? well yes. 2 seals per cylinder can contribute to vacuum leak at main intake manifold and its secondary intake manifold.
===================
What if this is an Ignition issue ? Sure it can be too.
The COP waveform analysis can identify such issue and you also need to do voltage drop testing just in case it is the power & ground is the bad boy or part of the overall bad boys.
If the wiring integrity ( 4 pin connector ) to the coil/COP is not so good, at high RPM it can cause misfire.
Our engine uses 4 wire COP which its transistor or switching circuit or driver which is handling the high power current is already inside the coil, no more at the ECM like say M271 EVO.
So ECM only supply low power signal to the pin #4 at the COP connector and while it can be the culprit, it is usually not....but if you do electrical integrity check, you must check it too.
Aside from the 4 pin connector at the COP, where else ? The splice or the parallel connection source of pin 2 (W11) and pin 3 (Z7/38z1) and pin 1 ( Z6z1 and Z6z2) <<< for COP/cylinder 2 and 3.
If you see pin 2 and pin 3 of 1.5mm wire size, we know that these wires carry the highest load. Pin 1 at 0.5mm is more of noise control and/or reporting to ECM of COP firing.
I use T1/4 or COP cylinder 4 as reference of the wiring.
Where is W11 ( ground) ?
C is a metal plate connecting A to B.
B is the the physical connection of Ground to cylinder head.
A is the first interconnect of splices to 1 single connection post/bolt.
All other splices for positive feed are inside this electrical box
Only when you see worrying voltage drop to COP connector, you will need to open up above electrical box....but if you are itchy handed like me, by all means clean them and tighten them.
For me, I run extra 6mm ground wire to W11 which is Bank 2 and its sister location at Bank 1, direct from alternator negative bus bar or body. I don't like "dirty-indirect" connection MB is using.
WILL CONTINUE.....................
Last edited by S-Prihadi; 10-17-2022 at 01:44 AM.
Reason: typo correction
Boroscope in use. Well might as well inspect cylinder liner scoring.
Attached WIS on cylinder liner/wall condition-inspection
===============================
Here are the fuses asignment if you want to verify amperage of the COPs using amperage clamp and a scope. Amperage values can speak information.
This is our engine. M276.8
When and if you will use pressure transducer for compression waveform analysis, it would be wise a second pressure sensor monitors the Intake Manifold Suction/Pressure waveform too.
So 1 show pressure, the other can show suction for a more complete overall picture.
Having access to a PiscoScope automotive version ( for reason of isolated grounds for all channels...sort of ), it can also let you see injector pintle opening.
To test fit of the female terminal of COP connector the wired one, if you do not have a SLK 2.8 MALE terminal, the next easiest one to use is welding tip cleaner rods.
I once had issue with M271 EVO of a friend. Mild misfire caused by poor/bad contact even at idling, but unlucky for me it is at the ECM side connector and not the dummy COP ( COP without driver ) connector.
The problem with a driver inside the ECM is, the pin used on ECM is the small MLK 1.2 ( 1.2mm wide ) fragile .......... but at the COP itself it is using the robust SLK2.8 ( 2.8mm wide).
I manage to "squeezed" back the MLK 1.2 female terminal to be tighter fit...crude, but it works.
At that time I do not yet have spare MLK 1.2 and SLK 2.8 terminals yet....so that welding tip cleaner rod is the smallest stiff rod I can use to test friction fit.
You cant test friction fit of the COP connector by pushing it into the COP, you will sense plastic body connector resistance + its seal, not the female terminal to male terminal friction itself.
Boroscope in use. Well might as well inspect cylinder liner scoring.
Attached WIS on cylinder liner/wall condition-inspection
===============================
Here are the fuses asignment if you want to verify amperage of the COPs using amperage clamp and a scope. Amperage values can speak information.
This is our engine. M276.8
When and if you will use pressure transducer for compression waveform analysis, it would be wise a second pressure sensor monitors the Intake Manifold Suction/Pressure waveform too.
So 1 show pressure, the other can show suction for a more complete overall picture.
Having access to a PiscoScope automotive version ( for reason of isolated grounds for all channels...sort of ), it can also let you see injector pintle opening.
11 difference RPM looks good.
Now use the Misfire Counter in Autel use its screen record and do WOT pull 1st and 2nd gear.
You can also do stationary RPM to 4,200 soft limited, maybe misfire can happen here too...turn ON HVAC to load up the engine.
Or use parking brake and main brake and do engine load test using D1 and D2 and using brake to fish out the misfire, if you prefer not to do WOT on the road.
11 difference RPM looks good.
Now use the Misfire Counter in Autel use its screen record and do WOT pull 1st and 2nd gear.
You can also do stationary RPM to 4,200 soft limited, maybe misfire can happen here too...turn ON HVAC to load up the engine.
Or use parking brake and main brake and do engine load test using D1 and D2 and using brake to fish out the misfire, if you prefer not to do WOT on the road.
I'll do it tommorow. One more qustion about fuel filter. I can't figure If this car is equiped with fuel filtre. Under the rear seat there are 2 fuel pumps ( by the part number). There is an inline filter or this pumps does have integrated filters? Thanks You very much for your help and your time.
Sounds like a good plan for intake valve carbon cleaning and the fuel filter too.
I thought you have replaced High Pressure Fuel Pump and surely fuel filter is an earlier consumeable item you would replace or maybe by previous owner/s.
BTW, did you get to see the misfire counter in action ?
Hi, i am the owner of a 2014 Mercedes E400 biturbo, with 2996 cc engine, 250.000 km on board. From few weeks i got some errors about misfires on cylinder 2 or 3, one by one. Only P0300 and P0302 or P0303 errors. We changed the spark plugs, the coils on 2 and 3 cyl, the injectors on 2 and 3 cyl, hpfp and camshaft sensors. The misfires are less than before but still there. Idle is ok, if you drive the car with slow accelerations it's ok, only on hard accelerations the misfires occure. Do you know how to figure out the problem?
I had the same issue, it was my low pressure fuel pump P1CCF means replace low pressure fuel pump. I think it's planned obsolescence
Looking at this forums since May 2018, I would say decent etiquette level is no higher than 10-20%.
For every newbie/s who only visit this forum when they have issue/s, 1 to 2 out 10 will not update the status of the problem when presented with possible solution/s.
It is quite a sad affair to see this because DIY forums won't grow or survive well if it fail to increase the good/worthy data collection or shared technical experiences from members.
If the newbie/s in question has access to proper scanner/s , their would be updated information on the progress is even more valuable if shared as it has DTC information or has live data
information which can help others in the future.
10-14-2022, 08:16 AM
, please
